"I don't see the math. There are only 16 days, legislative days, for the floor," Rep. Mario Diaz-Balart, a leading Republican immigration-reformer in the House, told the Miami Herald on Thursday.

"Unless someone has some magic potion," he said. "I don't see how there's time to go through the committee process and through the floor with what could ultimately be six or nine bills."

Diaz-Balart said there's not enough appetite among a majority of the Republican caucus right now. He said he wished that wasn't the case, and he hopes the House will tackle immigration reform early next year.

"I would have liked to have gotten it done when Obama got elected and we had a bill ready to go," he said, noting he began work-shopping a bill in 2008. "But reality is reality."

Complicating the issue: too many conservatives are worried about being tagged as too supportive of "amnesty" for illegal immigrants by supporting a pathway to citizenship. The Senate bill provided a path to citizenship for the estimated 11 million immigrants living here illegally and tightened border security.

Many saw the fierce conservative blowback against Republican Sen. Marco Rubio, an architect of the Senate bill, and want no part of it.

A few Republicans, including Miami Rep. Ileana Ros-Lehtinen, have signed on to a House version of the Senate bill sponsored by fellow Miami Rep. Joe Garcia, a Democrat.

But Diaz-Balart has held off. Not because he opposes Garcia's bill, he said, but because it hurts his standing in negotiating with Republicans in the House.

Immigration-reform advocates have lauded Garcia and have started to turn on Diaz-Balart when the representative first noted to the Washington Post that time essentially had expired in the House this year.

"House GOP reformers talk a good game, but the only action we see is them sweet talking and slow walking," Frank Sharry, executive director of the America's Voice advocacy group, said in a written statement.

"There's an existing majority in the House that would vote for reform right now. The only thing blocking it is the House GOP leadership," he said. "We expect reformers like Diaz-Balart to produce concrete proposals, not weak excuses for more delays and inaction."

Diaz-Balart said he can't force members to back a bill. And it can't be rushed.

Still, Diaz-Balart said, immigration-reform is good policy as well as good politics. Hispanics are growing farther and farther away from the GOP, where the tone over immigration reform is turning off this fastest-growing segment of the electorate.

"This isn't going away," he said.

Acknowledging immigration reform is a "long shot," he said he nevertheless remains optimistic that he can overcome a de facto House rule requiring him to get a majority of the Republican caucus — about 117 votes — to get a floor vote.

It just won't happen this year, and Diaz-Balart said he worries about the fact that it's easier to pass controversial legislation in non-election years.

"I don't know what the magic number is. There is a time next year when things get even more political, when difficult things don't get done," he said. "Is there a big difference between December and January? No. Is there a big difference between January and May? Yeah."

In a letter to fellow House Speaker John Boehner, R-Ohio, a Catholic, Cardinal Timothy Dolan, president of the U.S. Conference of Catholic Bishops and archbishop of New York, said the House must act before the end of the year.

Wrote Dolan: Immigration is "a challenge that has confounded our nation for years, with little action from our federally elected officials. It is a matter of great moral urgency that cannot wait any longer for action."